CODEWITHSUNDEEP
include-path
LinuxUser
LinuxUser

Reputation: 1

If a program has #include <abc/xyz.h>, where is the directory abc located?

When I run the program, I get the message:

error: abc/xyz.h: No such file or directory.

abc resides in the same directory as the C code of the program I am trying to run.

Upvotes: 0

Views: 509

Answers (1)

paxdiablo
paxdiablo

Reputation: 881553

The location to find headers is an implementation-defined thing, both for the <> and "" variants.

So, it depends on which actual implementation you're using.

The relevant bits of C99 are from 6.10.2, "Source file inclusion" (unchanged in C11), quoted below.

A preprocessing directive of the form

# include <h-char-sequence> new-line

searches a sequence of implementation-defined places for a header identified uniquely by the specified sequence between the < and > delimiters, and causes the replacement of that directive by the entire contents of the header. How the places are specified or the header identified is implementation-defined.

A preprocessing directive of the form

# include "q-char-sequence" new-line

causes the replacement of that directive by the entire contents of the source file identified by the specified sequence between the " delimiters. The named source file is searched for in an implementation-defined manner. If this search is not supported, or if the search fails, the directive is reprocessed as if it read

# include <h-char-sequence> new-line

with the identical contained sequence (including > characters, if any) from the original directive.

Many implementations will search the current directory for include files so, if your file is actually <current-directory>/abc/include/libsomething/xyz.h, you would use:

#include "abc/include/libsomething/xyz.h"

Alternatively, you could configure the compiler to modify the search paths, such as with gcc -Iabc/include/libsomething and just use:

#include "xyz.h"

Personally, I prefer the full specification since it makes conflicts less likely (you may have a different xyz.h somewhere else on the include-file search path).

Upvotes: 2

Related Questions